Variu, A;
Alam, S;
Zhao, C;
Chuang, CH;
Yu, Y;
Forero-Sánchez, D;
Ding, Z;
... Zhou, Z; + view all
(2024)
DESI mock challenge: Constructing DESI galaxy catalogues based on FastPM simulations.
Monthly Notices of the Royal Astronomical Society
, 527
(4)
pp. 11539-11558.
10.1093/mnras/stad3742.
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Abstract
Together with larger spectroscopic surveys such as the Dark Energy Spectroscopic Instrument (DESI), the precision of largescale structure studies and thus the constraints on the cosmological parameters are rapidly improving. Therefore, one must build realistic simulations and robust covariance matrices. We build galaxy catalogues by applying a halo occupation distribution (HOD) model upon the FASTPM simulations, such that the resulting galaxy clustering reproduces high-resolution N-body simulations. While the resolution and halo finder are different from the reference simulations, we reproduce the reference galaxy two-point clustering measurements – monopole and quadrupole – to a precision required by the DESI Year 1 emission line galaxy sample down to non-linear scales, i.e. k < 0.5 h Mpc−1 or s > 10 Mpc h−1. Furthermore, we compute covariance matrices based on the resulting FASTPM galaxy clustering – monopole and quadrupole. We study for the first time the effect of fitting on Fourier conjugate (e.g. power spectrum) on the covariance matrix of the Fourier counterpart (e.g. correlation function). We estimate the uncertainties of the two parameters of a simple clustering model and observe a maximum variation of 20 per cent for the different covariance matrices. Nevertheless, for most studied scales the scatter is between 2 and 10 per cent. Consequently, using the current pipeline we can precisely reproduce the clustering of N-body simulations and the resulting covariance matrices provide robust uncertainty estimations against HOD fitting scenarios. We expect our methodology will be useful for the coming DESI data analyses and their extension for other studies.
| Type: | Article |
|---|---|
| Title: | DESI mock challenge: Constructing DESI galaxy catalogues based on FastPM simulations |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stad3742 |
| Publisher version: | https://doi.org/10.1093/mnras/stad3742 |
| Language: | English |
| Additional information: | © The Author(s) 2023. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Galaxies: haloes, large-scale structure of Universe, cosmology: theory |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10186764 |
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